High resolution infrared spectroscopy using a spin-flip Raman laser: the bands of carbonyl sulphide near 1890 cm –1

The infrared combination band of carbonyl sulphide at 1892 cm–1 due to (1 20 0)â†�(0 00 0) forms a useful test spectrum for commissioning a spin-flip Raman laser. In addition to those from the ground state, lines which could be attributed to the hot band (1 31 0)â†�(0 11 0) with l-type doubling were observed. An analysis was performed assuming lower state constants from microwave values. The transition centre, the rotational constant and the centrifugal distortion constant for the (1 31 0)e state were found to be 1891.694(2) cm–1, 6087.03(12) MHz and 1.24(6) kHz, and for the (1 31 0)f state to be 1891.693(2) cm–1, 6100.22(11) MHz and 1.28(5) kHz respectively.